[comp.os.vms] Inter-process communication

GA.JPH@ISUMVS.BITNET.UUCP (09/16/87)

Chris Cebelenski <CEBELENS_CHR@CTSTATEU> writes:

>               I'm writing a Rogue type program for the Vax, that
>  will be multi-player.  As I understand it, I will need the
>  following:
>
>  1: A way of communications between processes. (Using NO PRIVS!!!)
>  2: A way of shareing files. (Again, no installs or privs!)
>  3: A way of making it cluster wide (if possible, using only NETMBX)
>
>   The program will be written in Vax Basic and Vax Pascal.  I hope to
>  avoid using QIO's if possible, but will if I have to.


   Well, I'm afraid I don't have an answers that you are going to want
to hear.  As far as I know, what you want to do is going to require
some privileges:

 1: A way of communications between processes.

Cooperating processes can communicate in a number of ways:

      a) Mailboxes
            (requires NETMBX/TMPMBX/PRMMBX)
            (requires SHMEM to place in shared memory)
            (requires SYSNAM or GRPNAM to place the logical name in
             the SYSTEM or GROUP logical name table)
      b) Global sections
            (requires SYSGBL if it is not to be restricted to a group)
            (requires SHMEM if it is to be in shared memory)
      c) Common event flags
            (only accessible to processes in the same group)
      d) Locks
            (requires SYSLCK if it is not to be restricted to a group)
      e) Files
            (see below)

 2: A way of sharing files.

      a) This only requires appropriate file and directory protection
         and specification of the proper sharing parameters on the file
         open.


 3: A way of making it cluster wide (if possible, using only NETMBX)

      a) Communication between nodes of a cluster is currently limited
         to DECnet (I believe) (i.e., NET-mailboxes, etc.).


   I know these are not the answers you want to hear, but my suggestion
would be that global sections and network mailboxes are the best path
to pursue:

      1) You can test it with no privs (by processes in the same group).

      2) If I was your system manager of all these privs SYSGBL is the
         one I would lose the least sleep about installing a user
         program with.


John Hascall
Iowa State University Computation Center
GAJPH@ISUMVS.BITNET

[The opinions expressed are strictly my own and are probably in no way
 related to any official position of ISUCC, Iowa State University, the
 State Board of Regents, the State of Iowa or any sane individual, ...
 although they could be reproduced by an infinite number of monkeys at
 an infinite number of terminals ... ]